Probing a pseudoscalar at the LHC in light of muon g − 2 and R(D(⁎)) excesses

We study the excesses of muon g−2 and R(D(⁎)) in the framework of a two-Higgs-doublet model with top quark flavor-changing neutral-current (FCNC) couplings. Considering the relevant theoretical and experimental constraints, we find that the muon g−2 and R(D(⁎)) excesses can be simultaneously explained in a parameter space allowed by the constraints. In such a parameter space the pseudoscalar (A) has a mass between 20 GeV and 150 GeV so that it can be produced from the top quark FCNC decay t→Ac. Focusing on its dominant decay A→ττ¯, we perform a detailed simulation on pp→tt¯→WbAc→jjbcττ¯ and find that the 2σ upper limits from a data set of 30 (100)fb−1 at the 13 TeV LHC can mostly (entirely) exclude such a parameter space.